The eChucK project is stuttering along nicely with it's dsPIC based approach for the first board. See the eChucK forum for details. I think, however, that starting out with dsPICs was kind of like biting off more than I can chew because of the software development effort and the need to buy a programmer and other obstacles. Far smarter would have been to do what I am thinking of here, which is to unite eChucK with Lunettas.

I guess the fundamental uniqueness of eChucK is a small but significant concept: the interconnect method. If you're not familiar, the idea is to make little postage stamp sized circuit boards that do simple things, much like individual Lunetta subcircuits, and then hook them up with solid wire. By using solid wire instead of stranded, the wire is strong enough to physically support the little boards so that one can build eChucK "sculptures" that make music, flash LEDs, or do other fun stuff. These 3D sculptures would be inexpensive enough to give as gifts or to form a kit that might possibly make synthesizers more accessible to kids of all ages (even 42 year old kids like me).

Enter Lunettas: I am now thinking of making a second batch of eChucK circuit boards that are Lunetta based. The new boards would each constitute a complete mini-synthesizer composed entirely of Lunetta circuits. There would be some minor changes such as the power supply being 5V instead of 3.3V, but of course that's simple enough.

I guess that I should also mention that even the novelty of the interconnect concept is not so novel as someone visited the chatroom and told me that he had the very same idea some time ago. I replied that when an idea's time has come, multiple people think of it around the same time, which history tells us is true. Anyway, back to the point of this post. My question to you is:

What circuits would you put on this proposed eChucK Lunetta board so that it forms a complete Lunetta-style synthesizer based on the eChucK interconnect concept?

Also, please feel free to offer any related thoughts or suggestions, especially creative ideas about how you would go about doing such a project. But you were going to do that anyway, right? Right.

This is a really cool idea and I can say for one that I would be interested in building a working lunetta sculpture, simple idea but cool if you actually did it! You have a variety of board ideas already it looks like, some of which I haven't heard of yet! Cool stuff

One board worth adding IMO: 4017->4051 melody generator!! I got this thing working and it is pretty cool and simple, but adds life to a couple clocks =]_________________http://www.soundclick.com/amplex

This is a really cool idea and I can say for one that I would be interested in building a working lunetta sculpture, simple idea but cool if you actually did it! You have a variety of board ideas already it looks like, some of which I haven't heard of yet! Cool stuff

One board worth adding IMO: 4017->4051 melody generator!! I got this thing working and it is pretty cool and simple, but adds life to a couple clocks =]

Thanks amplex! I'll add the melogy generator to the wish list for the board. Can you link me to an electro-music.com thread about it or an external link? Thanks a bunch!_________________"Let's make noise for peace." - Kijjaz

Great! That makes three of us and at e-teknet I can get four 3"x4" boards made for $100 and guess what? Since there were problems with the first boards they offered to make the second board order for HALF PRICE! That's for double-sided, top-side silk screened, but not routed into little bitty boards.

The routing, obviously, is expensive because it chews up router bits since they must travel horizontally. I do have a rather crude Dremel tool setup that does the job with some effort, but again that is not ideal. If anyone has a PCB shear we can have the boards delivered to that person and then chopped up and mailed out.

This is a bit of future planning, though, I have to move to a new apartment this month and get settled in, do the design, the board layout, and all the while I have a weekly electro-music.com ChucK Show to prepare for (which by the way was a TON of fun tonight). Let's take our time and plan it well and do it right.

If all the circuits won't fit on one little board like that, which I suspect is the case since we should be using through-hole parts so everyone can work them, then we'll make two boards and try to get the half price on the whole deal.

Lunettas meet eChucK, become friends, and make beautiful music together! What fun!

Yes, slacker, and they're doing it with the Klee too, it's like the idea popped up all over the place in DIY here more or less at the same time. Of course the basis of the idea is as old as synths themselves, but it's the new stuff we can do creatively that is really sort of expanding on the old concept.

Last night in the chatroom the conversation turned to the existing eChucK boards and i think it was droffset who asked me to post a photo, so here it is. I have a Dremel tool in a cheap drill press stand with a diamond cutting wheel and that does an OK job of sawing up the boards.

In the photo you see one board cut up in the foreground and others in the background.

Well I negotiated a lowball price of an extra $30 to do the whole thing, but they didn't do it. That's why we get the next batch for half price. But normally $30 or $60 additional on top of the $100 for the boards, which sounds like a lot to me.

For that price we could buy a hobbyist board shear and cut them up ourselves..._________________"Let's make noise for peace." - Kijjaz

The latest news is, I've been chatting with Macaba in the chatroom who is an occasional eChucK head, and he has identified this processor to include on the Lunetta board...

So one thing led to another and now we're talking about using 4-40 bolts for the interconnect and also doing the whole board in surface mount. This could be all pre-assembled or kit form, but I like the pre-assembled as not everyone has SMT equipment. The boards would come chopped up, so all the fun would be in connecting them up and programming the optionally used processor.

There was a little progress update that happened tonight so I thought it was time to post again. After giving it some thought, I feel that an eChucK Lunetta board should be simple and offer the Lunetta community something of value without necessarily being a full kit.

I think given the LED project, the guitar project and the ChucK Show every week plus moving is a bit much. So I'm slimming down the board to basically one module. It will be a boolean sequencer. I'm also thinking of adding a power supply and some output device like a karplus-strong algorithm or something.

I could make just a part, just a module to go into a Lunetta, or I could make a standalone product that can be populated for either standalone or module use. I also like the possibility of someone using the board in a modular synthesizer as well.

Anyway, long story short I wrote some ChucK code that simulates the board and how it might possibly sound. The audio sample is what happens when i drive the sum of the control voltages into a single high Q low-pass filter (Q=10).

Please let me know what you think, will it make a nice project or should I change directions?

Hi Les
It's seems an interesting project - kudus for your work on it. Thanks for the mp3.

Honestly - I've never messed with PICs, so I don't have much of a clue what you are doing here....or what the potential of this is. I might be more enthused if I knew more...
Here are just a few questions off the top of my head.

How would they interface to my existing Lunetta...or modular?
I expect someone has to write code for each 'module' idea and program the PIC - how would this be handled? What are the cost for the PICs and boards? How many processes can each one handle or is it one board , one process? What sort of physical control is there? Is this all ones and zeros for I/O?

Hi Bruce. There are no PICs on this board. It has a clock source, an 8 bit counter, 8 8-bit rocker dip switches with pullups, 8 eight input AND gate chips, one summing amp, and an eight input OR gate. I dunno if we can get the ANDs and ORs in standard CMOS.

What happens is when you set the dip switches, whenever all the set bits are one that term produces a one output. The summing amp creates a CV out of these outputs, and the OR gate sums them digitally.

Now that could be the whole board, with power supply external and how you want to use those two output signals as being up to you. Or I could add a power supply, a karplus-strong string synthesizer, and maybe even a speaker with LM386 driver. That would make it more of a full blown toy as well as make it for use in modulars and Lunettas. I dunno, just planning it.

I added the karplus-strong string synthesis algorithm to the ChucK file that I posted earlier and made an example audio file of it running one full cycle of 256 notes (four-quarter time). Samples below.

Bruce, to answer your other question, how to interface the board to your existing lunetta: The board will have power and signal connectors that you wire up to your panel. So it just looks like a big fat chip to you on a board.

The inputs are power, ground, and that's it. The outputs are CV and D, where CV is analog and D is digital. If the karplus-strong module is to be used, we run CV to the delay clock and D to the one-shot, as in the sample code of my previous post.

In summary: The board looks like a chip with three output signals and no input signals. That's how you interface it to your Lunetta.

Here is a board fragment showing the counter, the individual banks of ANDed DIP switiches with pullups, and the equivalent OR if i got that right for the logic output. Also an R2R ladder, btw where do the R and the 2R go on that? I never got into it before. Just posting progress, comments welcome.

It does seem interesting, if a bit complex. Is this what you used for your radio show pieces?

Yes, droffset, I use various forms of the Boolean Sequencer in the programs that I write for the show. Other people use other creative ideas. I guess it is a tad complex for a lunetta, though it's really just a counter, some switches, and some NAND gates._________________"Let's make noise for peace." - Kijjaz

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